Williams drops 1st set of US Open quarterfinal

Pironkova is playing in her first tournament in more than three years after taking time off to become a mother. She broke Williams to lead 3-2, then failed to convert two set points while Williams served at 5-3. But Pironkova served it out in the next game.

Serena Williams has dropped the first set of her U.S. Open quarterfinal against unseeded Tsvetana Pironkova by a 6-4 score. Pironkova is playing in her first tournament in more than three years after taking time off to become a mother.

She broke Williams to lead 3-2, then failed to convert two set points while Williams served at 5-3. But Pironkova served it out in the next game. She won 20 of the 25 points she served in that set.